Pneumatic tire for heavy load

Abstract

A pneumatic tire for heavy loads having a rubber composition for a tread rubber for a construction vehicle or the like, containing carbon black having a nitrogen adsorption specific surface area of 100 to 160 m.sup.2 /g, and an oil (dibutyl phthalate) absorption amount (DBP) of 80 to 130 ml/100 g, and silica having a nitrogen adsorption specific surface area of 210 to 260 m.sup.2 /g, and an oil absorption amount of 200 to 260 ml/100 g, by a total content of 40 to 70 parts by weight, in 100 parts by weight of isoprene rubber material, wherein the rubber composition contains 3 to 15 parts by weight of the total content. Further, the rubber composition contains 30 to 50 parts by weight of carbon black having a nitrogen adsorption specific surface area of 130 to 180 m.sup.2 /g, and an oil (dibutyl phthalate) absorption amount (DBP) of 80 to 120 ml/100 g, and 5 to 15 parts by weight of silica having a nitrogen adsorption specific surface area of 170 m.sup.2 /g or more, and 2.0 parts by weight or more of aging preventive agent, in 100 parts by weight of isoprene rubber material, wherein the compounding ratio of silica to carbon black (silica/carbon black) in the rubber composition is in a range of from 0.1 to 0.5 in the rubber composition.

Claims

1. A pneumatic tire for heavy loads having a rubber composition for tread rubber, comprising 30 to 50 parts by weight of carbon black having a nitrogen adsorption specific surface area of 130 to 180 m.sup.2 /g, and an oil (dibutyl phthalate) absorption amount (DBP) of 80 to 120 ml/100 g, and 5 to 15 parts by weight of silica having a nitrogen adsorption, specific surface area of 170 m.sup.2 /g or more, and 2.5 parts by weight or more of an aging preventive agent, in 100 parts by weight of isoprene rubber material, wherein the compounding ratio of silica to carbon black (silica/carbon black) in the rubber composition is in a range of from 0.1 to 0.5, and the rubber composition is free of a silane coupling agent.

2. A pneumatic tire for heavy loads of claim 1, wherein the carbon black has the nitrogen adsorption specific surface area of 140 to 170 m.sup.2 /g, and the oil (dibutyl phthalate) absorption amount (DBP) of 90 to 100 ml/100 g.

3. A pneumatic tire for heavy loads of claim 1, wherein the compounding ratio of silica to carbon black (silica/carbon black) is in a range of from 0.15 to 0.3.

4. A pneumatic tire for heavy loads of claim 2, wherein the compounding ratio of silica to carbon black (silica/carbon black) is in a range of from 0.15 to 0.3.

5. A pneumatic tire for heavy loads of claim 1, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 2.5 parts by weight or more in 100 parts by weight of the rubber material.

6. A pneumatic tire for heavy loads of claim 2, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 2.5 parts by weight or more in 100 parts by weight of the rubber material.

7. A pneumatic tire for heavy loads of claim 3, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 2.5 parts by weight or more in 100 parts by weight of the rubber material.

8. A pneumatic tire for heavy loads of claim 4, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 2.5 parts by weight or more in 100 parts by weight of the rubber material.

9. A pneumatic tire for heavy loads of claim 5, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 3.0 parts by weight or more in 100 parts by weight of the rubber material.

10. A pneumatic tire for heavy loads of claim 6, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 3.0 parts by weight or more in 100 parts by weight of the rubber material.

11. A pneumatic tire for heavy loads of claim 7, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 3.0 parts by weight or more in 100 parts by weight of the rubber material.

12. A pneumatic tire for heavy loads of claim 8, wherein the aging preventive agent is an amine aging preventive agent, and the amine aging preventive agent is contained by 3.0 parts by weight or more in 100 parts by weight of the rubber material.

13. A pneumatic tire for heavy loads of claim 9, wherein the amine aging preventive agent is at least one aging preventive agent selected from the group consisting of N-(1,3-dimethyl butyl)-N'-phenyl-p-phenylene diamine and N,N'-bis(1-ethyl-3-methyl pentyl)-p-phenylene diamine.

14. A pneumatic tire for heavy loads of claim 10, wherein the amine aging preventive agent is at least one aging preventive agent selected from the group consisting of N-(1,3-dimethyl butyl)-N'-phenyl-p-phenylene diamine and N,N'-bis(1-ethyl-3-methyl pentyl)-p-phenylene diamine.

15. A pneumatic tire for heavy loads of claim 11, wherein the amine aging preventive agent is at least one aging preventive agent selected from the group consisting of N-(1,3-dimethyl butyl)-N'-phenyl-p-phenylene diamine and N,N'-bis(1-ethyl-3-methyl pentyl)-p-phenylene diamine.

16. A pneumatic tire for heavy loads of claim 12, wherein the amine aging preventive agent is at least one aging preventive agent selected from the group consisting of N-(1,3-dimethyl butyl)-N'-phenyl-p-phenylene diamine and N,N'-bis(1-ethyl-3-methyl pentyl)-p-phenylene diamine.